Numerical aberrations of chromosome 8 and allelic loss at 8p in non-muscle-invasive urothelial carcinomas of the urinary bladder

Abstract

Objectives: Cytogenetic and molecular studies indicate that the development and progression of bladder cancer involves multiple and complex genetic events. We screened 39 primary T(a) and T1 transitional cell carcinomas of the urinary bladder for numerical changes of chromosome 8 and for the presence of relative allelic loss at 8p. The results were compared with the histopathologic stage and grade and with tumour recurrence. Methods: Thirty-nine paraffin-embedded transurethral resection specimens containing bladder cancer were examined by interphase cytogenetics with a probe specific for chromosome 8. DNA from tumour cells and normal tissue was prepared after microdissection. Allelic loss was assessed by PCR-based microsatellite analysis. Results: Numerical aberrations of chromosome 8 were present in 20 of the 39 cases (51.3%) and were significantly associated with a higher tumour grade and stage. Ten cases (25.6%) displayed allelic losses at 8p. Sixteen patients (41%) suffered from tumour recurrence, but Kaplan-Meier analysis and the log-rank test did not show any statistically significant correlation between tumour grade, stage, numerical aberrations of chromosome 8, allelic losses of 8p and freedom from disease recurrence. Conclusions: In this group of patients with non-muscle-invasive bladder cancers, numerical and structural aberrations at chromosome 8 are associated with a higher tumour grade and stage, but not with tumour recurrence. Copyright (C) 2000 S. Karger AG, Basel.